"NIA has announced a reward of Rs five lakh for anyone giving any information to follow up the case. As far as investigation is concerned, that is going on. Delhi Police and NIA are coordinating (with each other)," Union Home Secretary R K Singh told reporters here.
A man from Patna, who was arrested on charges of using a stolen ATM card, is already being interrogated by the joint team led by NIA for obtaining leads in the probe.
Singh said that a car which had been under scanner for suspicion of having ferried the perpetrators of the blast is "not connected" to the case.
Earlier in the day, Delhi Police and National Investigation Agency (NIA) teams met Delhi High Court Chief Justice Dipak Misra and discussed with him measures to beef up security in and around court premises and installation of CCTV cameras, metal-detectors and other security gadgets.
Official sources said the government has also decided to hand over to NIA the case relating to the May 25 low-intensity blast outside the Delhi High Court.
Earlier, Home Minister P Chidambaram held a high-level meeting to take stock of the situation in the wake of the blast even as investigators got preliminary forensic reports with regard to the explosion.
National Security Advisor (NSA) Shivshankar Menon and other senior officials in the security establishment attended the meeting.
Singh said he visited the victims of Wednesday's blast at the Delhi High Court who have been admitted in the Ram Manohar Lohia (RML) hospital and assured them of all the help they need.
"I visited RML hospital and met all patients and their relatives. They are appreciating the care they are being given by the doctors. We have told them that whenever they require, any assistance from experts from any other hospital, it will be provided," he said.
There are sufficient funds and medicines in the hospital, he said. Singh said a help desk has also been created in the RML for co-ordination between various hospitals.
Twelve people were killed and 75 injured in the powerful blast that took place outside gate number 5 of the court on Wednesday.